Condenser is the code the powers Steemit. I made an improvement to canonical linking:
On the Steem network, dApps have historically had an issue: search engines. With so many dApps, it's impossible for Google to decide what dApp to show for a post. Google had no way of knowing that DTube videos were to be shown on DTube, and not Steemit, as DTube videos are made as Steem posts.
However, there is a solution: the canonical tag. Websites can specify what URL the content was posted on originally. Historically, Steemit has set the canonical tag on Steemit posts to be Steemit, even if the post wasn't made on Steemit. Because Steemit is the most popular dApp, and the first, Google believes that other dApps are stealing Steemit's content, which is wrong.
However, there is a solution. Almost every dApp embeds the name of the app used to create, into the post. It doesn't put it directly in the post (some do, but most don't), but in the JSON metadata. This metadata section doesn't get displayed directly to those reading a post, but still contains important data. For example, it includes the tags of the post. This is also where dApps put the name and version of themselves.
I changed the code that runs Steemit (called Condenser), to change how it makes canonical links. Now, it parses the JSON metadata, and sees if it finds a dApp it knows about. If it does, it puts the link to the post that would be used on that dApp, in the canonical URL. It gets the list of dApps from the Steem Script library.
Here's what the canonical tag looks like now, on Steemit:
I did this in Condenser PR #2947.
